An adult zeratus crab is attracted to anything shiny, collecting anything that glitters from loose jewelry, gemstones, gold coins to pearls. It's not unusual to find any of these items adorning the sand castles they build, as they seem to compete with each other to see which crab has the largest and shiniest home. A zeratus crab's home is never complete as it continually builds onto it, building a giant sand castle as tall as a magi. Depending on where a crab lives, its sand castle can take on many different forms. Out in the wild, a crabs castle will be wild and unnatural looking, closer to civilization, they start to take on familiar shapes, from small huts, to large castles. It's not uncommon for a crab to build a miniature sand replica of their magi's keep. While they aren't the most social of creatures, their large pincers delivering a nasty pinch if picked up against their will, they will tolerate their magi handling them if offered a fresh fish or two.

Found on many of the beaches around the known world, zeratus crabs are a beautiful sight scuttling across the white sands as their colorful shells glimmer in the sun. Living for up to a century long, these crabs make for an ideal long term companion. Small in size, only reaching up to twenty-three centimeters in width, they make up for it with their attitude, rarely backing down if threatened, brandishing their pincers menacingly at would be attackers. They will eat almost anything they can catch, from mussels, snails, fish, and plants to carrion and even other smaller crabs. Zeratus crabs are excellent builders, building their homes on the beach with sand, small rocks, twigs and anything shiny that they can get their claws on, all held together with a slimy substance they produce that is nearly impossible to break once hardened. This substance makes these crabs quite popular among builders, making a building much more secure with a coat of hardened slime on the outside. This is especially useful in tropical locations where sudden storms can cause a lot of damage.